ISSN:
1432-2242
Schlagwort(e):
Key words Coffea
;
Coffee-tree
;
Internal transcribed spacer region
;
Nuclear ribosomal DNA
;
Molecular phylogeny
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract Phylogenetic relationships of Coffea species were estimated from the sequences of the internal transcribed spacer (ITS 2) region of nuclear ribosomal DNA. The ITS 2 region of 37 accessions belonging to 26 Coffea taxa and to three Psilanthus species was directly sequenced from polymerase chain reaction (PCR)-amplified DNA fragments. The level of variation was high enough to make the ITS 2 a useful tool for phylogenetic reconstruction. However, an unusual level of intraspecific variation was observed leading to some difficulty in interpreting rDNA sequence divergences. Sequences were analysed using Wagner parsimony as well as the neighbour-joining distance method. Coffea taxa were divided into several major groups which present a strong geographical correspondence (i.e. Madagascar, East Africa, Central Africa and West Africa). This organisation is well supported by cytogenetic evidence. On the other hand, the results were in contradiction with the present classification of coffee-tree taxa into two genera, namely Coffea and Psilanthus. Furthermore, additivity of parental rDNA types was not observed in the allotetraploid species C. arabica.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/s001220050500
Permalink
